Passenger restraint systems in automobiles are generally well suited to properly restrain adults but not well suited to properly restrain children. Accordingly, vehicle restraint systems must be supplemented by devices such as booster seats, which may be broadly defined as a seat that relies primarily on the vehicle's lap and shoulder belts to retain the seat in the vehicle and to restrain the child's torso, and includes a seat portion on which the child is seated to elevate the child above the vehicle's seating surface to a position in which the vehicle's shoulder belt is better positioned on the child, and may also include a back portion. A common construction technique for booster seats with backs is to mold the seat and back portions from rigid plastic and cover them with a cushion or pad.
Known booster seats designs suffer from several drawbacks. First, large L-shaped bodies (such as seats with back portions) tend to be relatively expensive and difficult to mold in one piece, especially if the seat includes wings and a lap belt path. Second, known booster seats do not adequately address the need to adjust and maintain the position of the vehicle shoulder belt relative to child's shoulder, particularly for children of different heights. Third, parents sometimes unknowingly use a booster seat for a child that is too small for the seat or a child that has outgrown the seat.
The manufacturing expense associated with a rigid molded body derives from the complex molding process required. One solution is to mold the seat as a plurality of separate, less complex, pieces and assemble the separate pieces into a rigid whole. Unfortunately, molding the seat as separate pieces requires additional tooling to mold the separate pieces and adds assembly steps, both of which add to the cost of manufacture. Thus, the savings due to less complex molding is offset by increased manufacturing and assembly costs. A molding technique that reduces complexity without increasing the number of molded pieces while allowing simple assembly would be welcome by seat manufacturers.
The failure to properly position the vehicle's shoulder belt relative to the child's shoulder can compromise the effectiveness of a booster seat. For optimum restraining effectiveness in an accident, the vehicle shoulder belt should lie on the child's shoulder. If the belt is positioned too high, the belt can impact the child's chin or neck, causing injury to soft tissue. If the shoulder belt is too low, it will lie off the child's shoulder, where it becomes relatively ineffective. It is therefore important to provide some mechanism for adjusting the shoulder belt's position to fit the child. Known devices for providing such adjustment suffer from drawbacks.
One design approach uses a fabric loop that is attached to the seat by hook and loop fasteners and which is wrapped around the shoulder belt to capture the belt and therefore to position the belt relative to the seat. One problem with this design approach is that he loops can be relatively easily dislodged as, for example, when the child shifts position in the car seat. When the loop becomes dislodged, it must be relocated, which can be inconvenient. A better approach would be an adjustable belt positioner that is firmly attached to the seat to avoid being inadvertently dislodged and, therefore, more convenient and effective.
The third problem, like the second, is directly related to the size of the child using the booster seat. Booster seats are designed to fit children that fall within a certain size range. Placing a child that is too tall or too short in the seat may results in improper placement of the shoulder belt on the child and therefore a less effective restraint. Although seats are typically provided with explicit instructions to the user as to the approach size range for the seat, careless or inattentive parents may overlook or ignore these instructions and place an over- or under-sized child in the seat. Proper use of the seat could be made more likely if the seat included a direct visual indicator of whether a child is sized to safely use the seat.